Here's why everybody is freaking out about methane on Mars

After almost a year of searching, NASA's Curiosity rover has turned up no traces of the four-pronged hydrocarbon known as methane. This special molecule is regarded by many as a chemical signature of past or present life on the red planet. That means there's no life on Mars, right? Wrong. » 9/20/13 10:04am 9/20/13 10:04am